Effect of Tb3+ Concentration on the Optical and Vibrational Properties of YBO3 Tri-doped with Eu3+, Ce3+, and Tb3+
MetadataShow full metadata
Structural and optical studies are reported of yttrium orthoborate YBO3 when tri-doped with Eu3þ, Ce3þ, and Tb3þ, focusing on the role of terbium concentration. Incorporation of Tb3þ affects emission properties for photoluminescence (PL) excited by near ultraviolet light. For constant cerium and europium concentrations, increasing the Tb3þ results in diminished PL from the Ce3þ and Tb3þ color centers. Simultaneously, the PL excitation bands related to both Ce3þ and Tb3þ increase in intensity for red emission from the Eu3þ. Results are consistent with a Ce3þ (Tb3þ)n Eu3þ energy transfer scheme, where (Tb3þ)n denotes a chain incorporating n terbium ions. A high red to orange PL intensity ratio is obtained, ranging from 1.34 to 2.09. Raman vibrational bands show a systematic change, with Tb3þ concentration, in the B3O9 ring terminal oxygen bending mode coordinated with the yttrium site where dopant ions substitute. The structural changes are interpreted as variations in the local neighborhood of these sites in the YBO3:Ce3þ,Tb3þ,Eu3þ crystal structure.